Explore the largest cave in the world

Son Doong cave in Vietnam

The Son Doong Cave in Vietnam is the largest cave in the world. It is located in Son Trach, Bo Trach District, Quang Binh province, Vietnam. The name "Son Doong" cave means "mountain river cave". It was created 2-5 million years ago by river water eroding away the limestone underneath the mountain where the limestone was weak, the ceiling collapsed creating huge skylights. Son Doong cave is more than 200 meters wide, 150 meters high, and approx 9 kilometres long. It has a jungle and river, and could fit a 40-storey skyscraper within its walls. It has caverns big enough to fit an entire city street inside them, twice as large as Deer Cave in Malaysia (currently considered the world's largest with 90 meters wide, 100 meters high and 2 kilometres long). But nobody knew any of that until about six years ago. A local man discovered the cave entrance in 1991, but British cavers were the first to explore it in 2009. Permits are required to access the cave and are made available on a limited basis. Only 500 permits were issued for the 2015 season, which runs from February to August.